1. Field of the Invention
The present invention relates to a cleaning device, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
In an electrophotographic image forming apparatus, a cleaning blade method using a cleaning unit has been known for removing developer remaining on an image bearing member (a member to be cleaned) after a developer image formed on the image bearing member has been transferred onto a recording medium to repeatedly use the image bearing member.
The cleaning blade method is a method for removing developer from a surface of the image bearing member by contacting a blade having elasticity with the surface of the image bearing member at a predetermined pressure.
In United States Patent Publication Application No. 5470635, a cleaning member has a configuration in which a blade is attached to a tip end of a sheet metal serving as a supporting member by shape forming. The cleaning member is fixed by attaching the sheet metal to a frame member with a screw or the like, to bring the cleaning member into contact with a surface of an image bearing member at a predetermined pressure.
An image forming apparatus such as a printer tends to be reduced in size, increased in speed, and enhanced in image quality as it spreads. With the reduction of the image forming apparatus in size, the size of an image bearing member is to be reduced. The image bearing member rotates fast when the image forming apparatus is to be increased in speed. More specifically, a blade, which contacts a surface of the image bearing member, slides on the surface of the image bearing member repeatedly at high speed. The temperature of the blade itself rises, so that the hardness of the blade is lowered. As a result, the friction force between the surface of the image bearing member and the blade rises. Thus, a driving torque for driving the image bearing member may increase, and the blade may warp. Further, developer with a spherical shape may have recently been used to enhance the image quality. In this case, a contact pressure of the blade on the image bearing member needs to be increased to remove the developer from the surface of the image bearing member, which is one of factors for confounding the above-mentioned problem.